So I remember I used to play with a mod called starminer, and one of the things that is added was a gravity block (I forget the name). What it did was you could input a radius, and then any players/mobs within that radius would "fall" towards that block instead of the ground, while their player model and camera rotated to reflect the new gravity. The mod has since become outdated and seemingly abandoned by the maker, who I believe is Japanese.
I was hoping someone would be able to make a mod that adds a single block similar to the one described above, that you can input a radius and multiplier into. The radius would determine far the blocks effects went, while the multiplier would effect how strong the gravity of the block is, i.e. setting the multiplier to 2 would draw entities to it twice as fast as they fall outside of the sphere of effect, while setting it to -1 would repel entities, allowing the possibility of walking along the inside edge of a constructed sphere. Models and cameras would also rotate respectively. For simplicity's sake, both in actual gameplay and coding, it might be best for the gravity to only pull along one axis (east, west, north, south, up, and down) at a time based off which direction would be the most traveled the entity made a straight shot for the block, rather than actually pulling towards the block resulting in diagonal gravity. Diagonal gravity would not only make walking in general hard, but I'd imaging it would be harder to code.
If possible, a bonus detail of this could be blocks such as torches and doors also rotating to reflect center of gravity, so if the multiplier is positive, torches on the "ground" point away from the gravity generator, and if the multiplier is negative, torches would point towards it. That kind of thing.
I'm willing to help (as much as I can) anyone who wants to work on this. I have no modding experience so I can't do it by myself but I'm pretty good at designing textures at least. Even if it's just one block this mod would mean to world to me.